Adult:
The adult peacock is unique in its appearance, characterised by a deep
reddish-brown ground colour to the wings with a striking, yellow-rimmed
bluish eye spot at the apex of each wing. The margin of each wing is a
darker, dull brown. Two thick black bands as long as the eye spot extend
down the forewing, with a yellow flush between them. A series of five
whitish spots form a line
parallel
with the margin of the forewing that runs through the eyespot and extends
halfway down the wing. The species exhibits little variation throughout its
range, although occasional individuals lack eye spots altogether.

In contrast to its extravagant
upperwings, the
underside is grey-brown and patterned to resemble bark, with a series of
irregular black bands of varying intensity running across it.

Larva: When approaching full size, peacock
caterpillars become black, covered with irregular white tubercles that give
the animal a speckled appearance. Six hairy 'spines' project from each body
segments Younger larvae are greyish-green, and can be found in large
aggregations on nettle leaves. Young larvae live within a silk web they spin
on nettle leaves.

Similar species: When seen from above, the peacock
butterfly is unmistakeable and can't be confused with any other species.
Some species, such as the painted lady, have similarly
cryptic underwings, but
these usually have some blue markings which are absent in the peacock. In
appearance and behaviour, early-stage larvae resemble those of the small
tortoiseshell (Aglais urticae).

The peacock butterfly is cosmopolitan in its foraging
habits and so can be encountered in most habitats. These butterflies are
common visitors to gardens. When searching for breeding sites, peacocks
particularly favour woodland edges, hedgerows and forest clearings with a
combination of sunny aspect and shade.

Elevation: 0-2,500 m

Larval food plants: Stinging nettles (Urtica
dioica) in most of the species' range. Pellitories (Parietaria
officianalis) will be used where stinging nettles are not indigenous.
Occasionally other nettle species and hops (Humulus) may be used.

Males are territorial, and lay claim to areas of open,
sunny ground around woodland edges and hedgerows, which they will abandon
only to pursue females. Peacocks may migrate during their flight season, but
in smaller numbers than in truly migratory species.

Diet: Nectar from willowblossoms is
preferred by adults emerging from hibernation. Buddleias are commonly used
as nectar sources by adult butterflies.

Flight season: June/August to October, although
animals may enter dormancy as early as July in unfavourable conditions.
Dormant animals emerge from hibernation between February and May, being most
common in late April. Butterflies have been emerging progressively earlier
over the last 30 years.

Breeding biology: Peacocks are typically
univoltine, but two broods a year have
occasionally been reported in favourable conditions, although these broods
are smaller than the first of the year. Dull green, spherical eggs are laid
in clutches of up to 500, often in several layers, on the underside of
nettle leaves.